In the artificial illumination arts, DC-DC converters are often employed in electronic ballasts to perform step or step down transformation of rectified input power prior to inversion to drive a lamp load. In high input voltage applications, the rectified input voltage may exceed the maximum voltage rating of medium voltage switches in conventional buck-boost and other DC-DC converter architectures. Accordingly, conventional ballast DC-DC converters required the use of expensive high voltage electronic components, such as switches rated for 1000V or more. In addition to the increased cost and component availability issues, such devices may suffer from high levels of conduction losses and thus present efficiency problems for the ballast. Accordingly, there is a need for improved DC-DC converters for high voltage electronic ballasts by which the above and other shortcomings of conventional devices can be mitigated or overcome.